Allow accessing headers from invalid responses

Author: jmartisk

client/api/src/main/java/io/smallrye/graphql/client/InvalidResponseException.java

@@ -1,5 +1,8 @@
 package io.smallrye.graphql.client;
 
+import java.util.List;
+import java.util.Map;
+
 /**
  * Marks a response that had unexpected contents and the client was unable to properly process it.
  * This can be either due to an error on the server side (returning non-conformant responses),
@@ -8,12 +11,30 @@
  */
 public class InvalidResponseException extends RuntimeException {
 
+    private final Map<String, List<String>> transportMeta;
+
     public InvalidResponseException(String message) {
         super(message);
+        this.transportMeta = null;
     }
 
     public InvalidResponseException(String message, Throwable cause) {
         super(message, cause);
+        this.transportMeta = null;
+    }
+
+    public InvalidResponseException(String message, Throwable cause, Map<String, List<String>> transportMeta) {
+        super(message, cause);
+        this.transportMeta = transportMeta;
+    }
+
+    /**
+     * Get transport-specific metadata that came from the server with the invalid response.
+     * For HTTP, these are the response headers. It can be null if headers aren't applicable, for example
+     * if this is coming from a message received over a WebSocket connection.
+     */
+    public Map<String, List<String>> getTransportMeta() {
+        return transportMeta;
     }
 
 }

client/implementation/src/main/java/io/smallrye/graphql/client/impl/ResponseReader.java

@@ -79,7 +79,8 @@ public static ResponseImpl readFrom(String input, Map<String, List<String>> head
         if (jsonResponse == null) {
             throw new InvalidResponseException(
                     "Unexpected response. Code=" + statusCode + ", message=\"" + statusMessage + "\", " +
-                            "body=\"" + input + "\"");
+                            "body=\"" + input + "\"",
+                    null, headers);
         }
         JsonObject data = null;
         if (jsonResponse.containsKey("data")) {

server/integration-tests/src/test/java/io/smallrye/graphql/tests/client/dynamic/error/InvalidResponseTest.java

@@ -0,0 +1,76 @@
+package io.smallrye.graphql.tests.client.dynamic.error;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.concurrent.ExecutionException;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.container.test.api.RunAsClient;
+import org.jboss.arquillian.junit.Arquillian;
+import org.jboss.arquillian.test.api.ArquillianResource;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.EmptyAsset;
+import org.jboss.shrinkwrap.api.spec.WebArchive;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import io.smallrye.graphql.client.InvalidResponseException;
+import io.smallrye.graphql.client.vertx.dynamic.VertxDynamicGraphQLClient;
+import io.smallrye.graphql.client.vertx.dynamic.VertxDynamicGraphQLClientBuilder;
+
+/**
+ * Verify that the client allows access to HTTP response headers when an invalid response is received.
+ * In this test, a servlet is used to return a 418 I'm a teapot response with a custom header.
+ * The client then makes a request and verifies that the InvalidResponseException contains the custom header.
+ */
+@RunWith(Arquillian.class)
+@RunAsClient
+public class InvalidResponseTest {
+
+    @Deployment
+    public static WebArchive deployment() {
+        return ShrinkWrap.create(WebArchive.class, "invalid-response-test.war")
+                .addAsWebInfResource(EmptyAsset.INSTANCE, "beans.xml")
+                .addClasses(ErrorServlet.class);
+    }
+
+    @WebServlet(urlPatterns = { "/graphql" })
+    public static class ErrorServlet extends HttpServlet {
+        @Override
+        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+            resp.setStatus(418); // I'm a teapot
+            resp.setHeader("Teapot-Color", "Yellow");
+        }
+    }
+
+    @ArquillianResource
+    URL testingURL;
+
+    private static VertxDynamicGraphQLClient client;
+
+    @Before
+    public void prepare() {
+        client = (VertxDynamicGraphQLClient) new VertxDynamicGraphQLClientBuilder()
+                .url(testingURL.toString() + "graphql")
+                .build();
+    }
+
+    @Test
+    public void receiveImATeapotResponse() throws ExecutionException, InterruptedException {
+        try {
+            client.executeSync("{}");
+            Assert.fail();
+        } catch (InvalidResponseException ex) {
+            Assert.assertEquals("Yellow", ex.getTransportMeta().get("Teapot-Color").get(0));
+        }
+    }
+
+}